Souaf Manel, Baira Mourad, Nasr Olfa, Alouane Mohamed Helmi Hadj, Maaref Hassen, Sfaxi Larbi, Ilahi Bouraoui
Laboratoire de Micro-Optoélectronique et Nanostructures, Faculté des Sciences, Avenue de l'environnement, Université de Monastir, Monastir 5019, Tunisia.
King Saud University, Department of Physics & Astronomy, College of Sciences, P.O. 2455, Riyadh 11451, Saudi Arabia.
Materials (Basel). 2015 Jul 24;8(8):4699-4709. doi: 10.3390/ma8084699.
This work reports on theoretical and experimental investigation of the impact of InAs quantum dots (QDs) position with respect to InGaAs strain reducing layer (SRL). The investigated samples are grown by molecular beam epitaxy and characterized by photoluminescence spectroscopy (PL). The QDs optical transition energies have been calculated by solving the three dimensional Schrödinger equation using the finite element methods and taking into account the strain induced by the lattice mismatch. We have considered a lens shaped InAs QDs in a pure GaAs matrix and either with InGaAs strain reducing cap layer or underlying layer. The correlation between numerical calculation and PL measurements allowed us to track the mean buried QDs size evolution with respect to the surrounding matrix composition. The simulations reveal that the buried QDs' realistic size is less than that experimentally driven from atomic force microscopy observation. Furthermore, the average size is found to be slightly increased for InGaAs capped QDs and dramatically decreased for QDs with InGaAs under layer.
本工作报道了关于InAs量子点（QD）相对于InGaAs应变降低层（SRL）位置影响的理论和实验研究。所研究的样品通过分子束外延生长，并通过光致发光光谱（PL）进行表征。通过使用有限元方法求解三维薛定谔方程，并考虑晶格失配引起的应变，计算了量子点的光学跃迁能量。我们考虑了在纯GaAs基质中、带有InGaAs应变降低帽层或底层的透镜形状InAs量子点。数值计算与PL测量之间的相关性使我们能够追踪平均掩埋量子点尺寸相对于周围基质成分的演变。模拟结果表明，掩埋量子点的实际尺寸小于通过原子力显微镜观察实验得出的尺寸。此外，发现对于有InGaAs帽层的量子点，平均尺寸略有增加，而对于有InGaAs底层的量子点，平均尺寸则显著减小。
